/* * jpeglib.h * * Copyright (C) 1991-1994, Thomas G. Lane. * This file is part of the Independent JPEG Group's software. * For conditions of distribution and use, see the accompanying README file. * * This file defines the application interface for the JPEG library. * Most applications using the library need only include this file, * and perhaps jerror.h if they want to know the exact error codes. *//* * First we include the configuration files that record how this * installation of the JPEG library is set up.  jconfig.h can be * generated automatically for many systems.  jmorecfg.h contains * manual configuration options that most people need not worry about. */#ifndef JCONFIG_INCLUDED	/* in case jinclude.h already did */#include "jconfig.h"		/* widely used configuration options */#endif#include "jmorecfg.h"		/* seldom changed options *//* Various constants determining the sizes of things. * All of these are specified by the JPEG standard, so don't change them * if you want to be compatible. */#ifndef DCTSIZE#define DCTSIZE		    8	/* The basic DCT block is 8x8 samples */#endif#ifndef DCTSIZE2#define DCTSIZE2	    64	/* DCTSIZE squared; # of elements in a block */#endif#define NUM_QUANT_TBLS      4	/* Quantization tables are numbered 0..3 */#define NUM_HUFF_TBLS       4	/* Huffman tables are numbered 0..3 */#define NUM_ARITH_TBLS      16	/* Arith-coding tables are numbered 0..15 */#define MAX_COMPS_IN_SCAN   4	/* JPEG limit on # of components in one scan */#define MAX_SAMP_FACTOR     4	/* JPEG limit on sampling factors */#define MAX_BLOCKS_IN_MCU   10	/* JPEG limit on # of blocks in an MCU *//* This macro is used to declare a "method", that is, a function pointer. * We want to supply prototype parameters if the compiler can cope. * Note that the arglist parameter must be parenthesized! */#ifdef HAVE_PROTOTYPES#define JMETHOD(type,methodname,arglist)  type (*methodname) arglist#else#define JMETHOD(type,methodname,arglist)  type (*methodname) ()#endif/* Data structures for images (arrays of samples and of DCT coefficients). * On 80x86 machines, the image arrays are too big for near pointers, * but the pointer arrays can fit in near memory. */typedef JSAMPLE FAR *JSAMPROW;	/* ptr to one image row of pixel samples. */typedef JSAMPROW *JSAMPARRAY;	/* ptr to some rows (a 2-D sample array) */typedef JSAMPARRAY *JSAMPIMAGE;	/* a 3-D sample array: top index is color */typedef JCOEF JBLOCK[DCTSIZE2];	/* one block of coefficients */typedef JBLOCK FAR *JBLOCKROW;	/* pointer to one row of coefficient blocks */typedef JBLOCKROW *JBLOCKARRAY;		/* a 2-D array of coefficient blocks */typedef JBLOCKARRAY *JBLOCKIMAGE;	/* a 3-D array of coefficient blocks */typedef JCOEF FAR *JCOEFPTR;	/* useful in a couple of places *//* Types for JPEG compression parameters and working tables. *//* DCT coefficient quantization tables. */typedef struct {  /* This field directly represents the contents of a JPEG DQT marker.   * Note: the values are always given in zigzag order.   */  UINT16 quantval[DCTSIZE2];	/* quantization step for each coefficient */  /* This field is used only during compression.  It's initialized FALSE when   * the table is created, and set TRUE when it's been output to the file.   * You could suppress output of a table by setting this to TRUE.   * (See jpeg_suppress_tables for an example.)   */  boolean sent_table;		/* TRUE when table has been output */  /* NB: there are additional private fields in an actual quantization data   * structure, so don't allocate one directly.  Use jpeg_alloc_quant_table.   */} JQUANT_TBL;/* Huffman coding tables. */typedef struct {  /* These two fields directly represent the contents of a JPEG DHT marker */  UINT8 bits[17];		/* bits[k] = # of symbols with codes of */				/* length k bits; bits[0] is unused */  UINT8 huffval[256];		/* The symbols, in order of incr code length */  /* This field is used only during compression.  It's initialized FALSE when   * the table is created, and set TRUE when it's been output to the file.   * You could suppress output of a table by setting this to TRUE.   * (See jpeg_suppress_tables for an example.)   */  boolean sent_table;		/* TRUE when table has been output */  /* NB: there are additional private fields in an actual Huffman-table data   * structure, so don't allocate one directly.  Use jpeg_alloc_huff_table.   */} JHUFF_TBL;/* Basic info about one component (color channel). */typedef struct {  /* These values are fixed over the whole image. */  /* For compression, they must be supplied by parameter setup; */  /* for decompression, they are read from the SOF marker. */  int component_id;		/* identifier for this component (0..255) */  int component_index;		/* its index in SOF or cinfo->comp_info[] */  int h_samp_factor;		/* horizontal sampling factor (1..4) */  int v_samp_factor;		/* vertical sampling factor (1..4) */  int quant_tbl_no;		/* quantization table selector (0..3) */  /* These values may vary between scans. */  /* For compression, they must be supplied by parameter setup; */  /* for decompression, they are read from the SOS marker. */  int dc_tbl_no;		/* DC entropy table selector (0..3) */  int ac_tbl_no;		/* AC entropy table selector (0..3) */    /* Remaining fields should be treated as private by applications. */    /* These values are computed during compression or decompression startup: */  /* Component's size in DCT blocks.   * Any dummy blocks added to complete an MCU are not counted; therefore   * these values do not depend on whether a scan is interleaved or not.   */  JDIMENSION width_in_blocks;  JDIMENSION height_in_blocks;  /* Size of a DCT block in samples.  Always DCTSIZE for compression.   * For decompression this is the size of the output from one DCT block,   * reflecting any scaling we choose to apply during the IDCT step.   * Values of 1,2,4,8 are likely to be supported.  Note that different   * components may receive different IDCT scalings.   */  int DCT_scaled_size;  /* The downsampled dimensions are the component's actual, unpadded number   * of samples at the main buffer (preprocessing/compression interface), thus   * downsampled_width = ceil(image_width * Hi/Hmax)   * and similarly for height.  For decompression, IDCT scaling is included, so   * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)   */  JDIMENSION downsampled_width;	 /* actual width in samples */  JDIMENSION downsampled_height; /* actual height in samples */  /* This flag is used only for decompression.  In cases where some of the   * components will be ignored (eg grayscale output from YCbCr image),   * we can skip most computations for the unused components.   */  boolean component_needed;	/* do we need the value of this component? */  /* These values are computed before starting a scan of the component: */  int MCU_width;		/* number of blocks per MCU, horizontally */  int MCU_height;		/* number of blocks per MCU, vertically */  int MCU_blocks;		/* MCU_width * MCU_height */  int MCU_sample_width;		/* MCU width in samples, MCU_width*DCT_scaled_size */  int last_col_width;		/* # of non-dummy blocks across in last MCU */  int last_row_height;		/* # of non-dummy blocks down in last MCU */} jpeg_component_info;/* Known color spaces. */typedef enum {	JCS_UNKNOWN,		/* error/unspecified */	JCS_GRAYSCALE,		/* monochrome */	JCS_RGB,		/* red/green/blue */	JCS_YCbCr,		/* Y/Cb/Cr (also known as YUV) */	JCS_CMYK,		/* C/M/Y/K */	JCS_YCCK		/* Y/Cb/Cr/K */} J_COLOR_SPACE;/* Common fields between JPEG compression and decompression master structs. */#define jpeg_common_fields \  struct jpeg_error_mgr * err;	/* Error handler module */\  struct jpeg_memory_mgr * mem;	/* Memory manager module */\  struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\  boolean is_decompressor;	/* so common code can tell which is which */\  int global_state		/* for checking call sequence validity *//* Routines that are to be used by both halves of the library are declared * to receive a pointer to this structure.  There are no actual instances of * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct. */struct jpeg_common_struct {  jpeg_common_fields;		/* Fields common to both master struct types */  /* Additional fields follow in an actual jpeg_compress_struct or   * jpeg_decompress_struct.  All three structs must agree on these   * initial fields!  (This would be a lot cleaner in C++.)   */};typedef struct jpeg_common_struct * j_common_ptr;typedef struct jpeg_compress_struct * j_compress_ptr;typedef struct jpeg_decompress_struct * j_decompress_ptr;/* Master record for a compression instance */struct jpeg_compress_struct {  jpeg_common_fields;		/* Fields shared with jpeg_decompress_struct */  /* Destination for compressed data */  struct jpeg_destination_mgr * dest;  /* Description of source image --- these fields must be filled in by   * outer application before starting compression.  in_color_space must   * be correct before you can even call jpeg_set_defaults().   */  JDIMENSION image_width;	/* input image width */  JDIMENSION image_height;	/* input image height */  int input_components;		/* # of color components in input image */  J_COLOR_SPACE in_color_space;	/* colorspace of input image */  double input_gamma;		/* image gamma of input image */  /* Compression parameters --- these fields must be set before calling   * jpeg_start_compress().  We recommend calling jpeg_set_defaults() to   * initialize everything to reasonable defaults, then changing anything   * the application specifically wants to change.  That way you won't get   * burnt when new parameters are added.  Also note that there are several   * helper routines to simplify changing parameters.   */  int data_precision;		/* bits of precision in image data */  int num_components;		/* # of color components in JPEG image */  J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */  jpeg_component_info * comp_info;  /* comp_info[i] describes component that appears i'th in SOF */    JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];  /* ptrs to coefficient quantization tables, or NULL if not defined */    JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];  JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];  /* ptrs to Huffman coding tables, or NULL if not defined */    UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */  UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */  UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */    boolean arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */  boolean interleave;		/* TRUE=interleaved output, FALSE=not */  boolean optimize_coding;	/* TRUE=optimize entropy encoding parms */  boolean CCIR601_sampling;	/* TRUE=first samples are cosited */  int smoothing_factor;		/* 1..100, or 0 for no input smoothing */    /* The restart interval can be specified in absolute MCUs by setting   * restart_interval, or in MCU rows by setting restart_in_rows   * (in which case the correct restart_interval will be figured   * for each scan).   */  unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */  int restart_in_rows;		/* if > 0, MCU rows per restart interval */  /* Parameters controlling emission of special markers. */  boolean write_JFIF_header;	/* should a JFIF marker be written? */  /* These three values are not used by the JPEG code, merely copied */  /* into the JFIF APP0 marker.  density_unit can be 0 for unknown, */  /* 1 for dots/inch, or 2 for dots/cm.  Note that the pixel aspect */  /* ratio is defined by X_density/Y_density even when density_unit=0. */  UINT8 density_unit;		/* JFIF code for pixel size units */  UINT16 X_density;		/* Horizontal pixel density */  UINT16 Y_density;		/* Vertical pixel density */  boolean write_Adobe_marker;	/* should an Adobe marker be written? */    /* State variable: index of next scanline to be written to   * jpeg_write_scanlines().  Application may use this to control its   * processing loop, e.g., "while (next_scanline < image_height)".   */